The present work is devoted to the synthesis of manganese oxides such as OMS-2 type and determination the sorption mechanism of Sr(II) ions. Nanoscale manganese oxides (NMO) sorbents were obtained by the sol-gel method using polyvinyl alcohol (PVA) and two types of inorganic reducing agents – H2O2 and MnCl2. The prepared sorbents demonstrated the high sorption affinity towards stable Sr(II) ions (sorption capacity is 200-220 mg∙g-1) and 85Sr radionuclides (distribution coefficient is (0.19-3.67) ×105 cm3∙g-1). The results of determining the chemical composition indicated that after sorption Sr ions included in the composition of sorbents (K(0.053-0.073) Sr(0.015-0.023) MnO2-z for samples obtained with PVA as reducing agent, and K(0.0225-0.086)Sr(0.0006-0.003)MnO2-x for H2O2 and MnCl2) instead part of potassium ions from initial NMO (K(0.106-0.116)MnO2-y and K(0.0299-0.155)MnO2-x). Also this hypothesis is confirmed by the X-ray analysis. In support of the ion exchange mechanism, we have the fact that, there are peaks of K2Mn4O8 phase on X-rays patterns before the adsorption of Sr (II) ions, and Sr0.72Mn8O16 (inorganic reducing agents), SrMnO3 (PVA). In the latter case, also SrCO3 phase was detected on X-rays patterns. It confirms that the chemisorption mechanism in case of PVA as a reduction agent. Formation of carbonate was due to interaction adsorbed strontium with thermolysis products of PVA. SEM-EDX data shown a uniform distribution of the strontium on the surface of the sorbents obtained using H2O2 and MnCl2. For the PVA derived NMO sorbents strontium has a discontinuous distribution predominantly in place with high carbon content. The sorption behaviour of Sr (II) ions onto manganese oxides with layered and tunnel structures by means XRD, SEM-EDX, chemical analysis were established. Thus it can be concluded that, depending on the type of the reducing agent is implemented mainly ion exchange (H2O2 and MnCl2 reducing agents) or ion exchange mechanism with chemisorption (PVA as reducing agent).